1. Field of the Invention
The present invention relates in general to electrochromic materials for use in electrochromic devices, and more particularly, to anodic electrochromic materials comprising a first moiety, such as a metallocene or a substituted metallocene, and a second moiety having one or more constituent(s) which serve to increase the solubility of the first moiety in an associated solvent relative to the solubility of the first moiety without the second moiety.
2. Background Art
Electrochromic devices have been known in the art for several years. Furthermore, experimentation associated with the utilization of metallocenes and simple substituted metallocenes as anodic electrochromic materials has also been explored. While the utilization of such anodic electrochromic materials in devices such as electrochromic mirrors and windows has been identified, the solubility characteristics of many of these anodic electrochromic materials remains problematic.
It is therefore an object of the present invention to provide an anodic electrochromic material with a solublizing moiety that remedies the aforementioned detriments and/or complications associated with the incorporation of the above-identified anodic electrochromic materials into a solvent at an operatively acceptable concentration.
The present invention is directed to an electrochromic medium for use in an electrochromic device comprising: (a) at least one solvent; (b) a cathodic electrochromic material; and (c) an anodic electrochromic material which includes (1) a first moiety, wherein the first moiety comprises a metallocene or a substituted metallocene, and (2) a second moiety, wherein the second moiety comprises at least one constituent which serves to increase solubility of the first moiety in the at least one solvent relative to the first moiety without the second moiety.
In another aspect of the invention, an electrochromic device is disclosed as comprising: (a) at least one substantially transparent substrate; and (b) an electrochromic medium which comprises (1) at least one solvent, (2) a cathodic electrochromic material, and (3) an anodic electrochromic material which includes a first moiety, wherein the first moiety comprises a metallocene or a substituted metallocene, and a second moiety, wherein the second moiety comprises at least one constituent which serves to increase solubility of the first moiety in the at least one solvent relative to the first moiety without the second moiety.
In a preferred embodiment of the invention, the first moiety is selected from the group comprising ferrocene, substituted ferrocenes, and mixtures thereof, and the second moiety is selected from the group comprising nitriles, nitro constituents, sulfoxides, sulfonates, phosphonium constituents, phosphonates, phosphonites, ammonium constituents, viologens including bipyridinyl constituents, carbonyls including carbonates, carbamates, ketones, esters, and amides, ethers including polyethers, amines including tertiary amines, alkenes, alkynes, and mixtures thereof.
The present invention is also directed to an anodic electrochromic material for use in an electrochromic device comprising: (a) a first moiety, wherein the first moiety comprises a metallocene or a substituted metallocene; and (b) a second moiety, wherein the second moiety comprises at least one constituent which serves to increase solubility of the first moiety in an associated solvent relative to the first moiety without the second moiety, and wherein the second moiety is selected from the group comprising nitrites, nitro constituents, sulfoxides, sulfonates, phosphonium constituents, phosphonates, phosphonites, polyethers, viologens including bipyridinyl constituents, carbonyls including carbonates, carbamates, ketones, cyclic esters, and amides, and mixtures thereof.